With legalization just around the corner (October 17th, y’all), Stats Canada is amping up their reporting on marijuana-related behaviour and their latest survey results are understandably causing some concern. Their latest quarterly survey found that of the 4.6 million participants who admitted to using cannabis in the past three months, almost 570,000 (about 14 per cent of respondents with valid drivers licences) drove within two hours of using.

The same study also had 1.4 million respondents (about five per cent) report getting into a car driven by a person who had used marijuana within two hours. That stat was notably higher among respondents who admitted to using cannabis regularly themselves — in that group, about 25 per cent reported being the passenger of a high driver.

One of the most pressing concerns for lawmakers during the legalization process has been how to detect and enforce laws surrounding driving under the influence. While the Breathalyzer test and other roadside evaluations are effective for determining if someone is intoxicated with alcohol, tests for marijuana use are far less reliable.

The first marijuana testing device that looks to be approved for police use in Canada is the DrugTest 5000 from Germany-based medical and safety technology company Dräger. The machine processes a saliva sample and tests for a range of drugs including cannabis. While the manufacturers claim the system is “designed for easy drug screening and accurate results,” a Norwegian study of the device revealed that it might not be the miracle test it claims to be.

According to the evaluation of the device conducted in 2015 and published in February of this year, the DrugTest 5000 “did not absolutely correctly identify DUID [driving under the influence of drugs] offenders due to fairly large proportions of false-positive or false-negative results compared to drug concentrations in blood.” Law enforcement admitted that while results were not always accurate and took an average of 50 minutes to process, the machine was still a “valuable tool” for apprehending people driving under the influence. The same machine was used in Australia and police there reported that it appeared to be accurate in about two thirds of cases.

CTV News also notes that the DrugTest 5000 works best in environments ranging from four to 40 degrees Celsius, calling into question how accurate it would be in the Canadian winter.

Unfortunately, even with all its limitations, the DrugTest 5000 appears to be one of the most viable options out there for testing THC levels in blood and looks to be on its way to approval by the Canadian federal government for roadside use.

Bottom line: please just don’t drive under the influence of any drug ever. Thank you.